Help!

So I had sex about a week and a bit ago and I had it twice, Sunday and Monday. And we used a Condom but before he put it on he put it into me a little bit. He hadn't comed yet. And now I'm getting worried cause my boobs are starting to get abit sore. I am due for my period next weekend but am starting to get worried that I am pregnant, I am 16 and if my mum found out I would be dead! And I am unable to buy a pregnancy test. Any advice people?